00:01
The accompanying data represent the pulse rates beats per minute of nine students enrolled in a statistics course.
00:07
We're going to treat these nine students as a population, and we're going to compute the population mean.
00:15
And we can do that by hand or with statistical software, we can add all those values up and divide by nine.
00:20
And when we do, we get a mean of 77 .2.
00:25
And since we're dealing with a population mean, let's go ahead and use mu.
00:31
So the mu is 77 .2.
00:35
For part b, compute the population variance.
00:41
So the population variance, we can again do this by hand, or we can use statistical software.
00:49
If we do this by hand, we have to subtract 77 .2 from each of these values, and then square that difference.
00:55
Then find the mean of those squared differences.
01:00
And when you do that, you're going to get a population variance of 80 .623.
01:09
We can take the square root of that to find our population standard deviation, which would be 8 .979.
01:19
So for part d, what value is the 70th percentile for the dataset? well, we can take 70 divided by 100 to put in decimal form times our nine values will tell us that the sixth, 6 .3, but really about the sixth value, is going to be the 70th percentile.
01:44
Now, we have to be careful because our data is not put into order, ascending order.
01:51
So this 6 .3 represents an ordered set of data.
01:55
So if we count in by order, we have one, two, three, four, five, six.
02:08
So counting in six when the data is in order puts us at 81...